1. Field of the Invention
The present invention relates generally to an apparatus and method for creating a three-dimensional caricature, and more particularly to an apparatus and method for creating a three-dimensional caricature having a high degree of similarity to user's face by precisely extracting feature point information on facial features and modifying a three-dimensional polygon face basic model based on the feature point information through the use of an Active Shape Model (ASM) technique specialized for faces.
2. Description of the Prior Art
Typically, a caricature means a drawing intended to give an effect of comicality, humor, satire, etc., with such materials as persons or personified animals and plants, including such senses as a user's curiosity, an indirect satisfaction, an ideal person imagined by an individual, etc. Although caricatures have mainly been utilized as advertising measures by entertainers or sportsmen, presently it is being widely used by the general public.
In addition, although caricatures have traditionally been created manually through work by a specialized caricature designer, techniques capable of creating caricatures without any aid of the specialized caricature designer have been developed as the general public interest in caricatures has increased.
As one example of these techniques, there is a method in which a user selects and combines clip art samples required to form facial contours of an eye, nose, mouth, etc., from a clip art database, and adds various accessories, clothes, etc. for creating a final caricature. However, this method evokes great discontent due to lack of similarity derived from great difficulty of selection of clip art samples closely resembling the user's own facial features.
The Korean Patent Laid-Open Publication No. 2000-63391 (entitled “Caricature Creation Method”) discloses a method of creating a caricature, in which an entire facial shape is first completed from a face in photograph, then the position, ratio and kind of each facial feature to be applied to the facial shape are calculated, and finally models for facial features are extracted from a database previously constructed for each facial feature of various sizes and then these models are combined together. However, in this method, it is almost impossible to extract precise feature points for facial features since only information on the position of each facial feature with respect to the size of a face is used. Therefore, this makes it difficult to create a caricature closely resembling the user's own facial features.
Further, The Korean Patent Laid-Open Publication No. 2000-49421 (entitled “Caricature Creation System and Caricature Creation Method Using the System”) discloses a method in which each part in a photograph edited through software is compared to a caricature for each part of a face, then each part of the face requiring modification is replaced with data stored in a database for completing a caricature for an entire face. However, this method is substantially limited by the impossibility of the creation of a caricature having colors because of a requirement for the photograph editing process in which original data consisting of natural colors through a color tone conversion are separated into black and white.
In addition, the Korean Patent Laid-Open Publication No. 2000-64110 (entitled “Automatic Caricature Creation Apparatus and Method Based On a Facial Image”) discloses a method in which information on the shape of face is extracted by using information on correspondence points of an input facial image with a reference image and then the facial image is synthesized again based on the extracted information for obtaining more natural and elaborate caricature images. However, this method takes a simple scheme that a prepared reference image is synthesized with a facial image, as in the Korean Patent Laid-Open Publication No. 2000-63391, and particularly lacks a definite explanation about the extraction of facial feature points from the facial image.
All the aforementioned disclosures are directed to two-dimensional caricature creation. On the other hand, studies for a three-dimensional caricature creation using face-modeling techniques are briskly progressing at present.
As one of techniques for three-dimensional caricature creation, U.S. Pat. No. 5,960,099 (entitled “System and Method for Creating a Digitized Likeness of Persons”) discloses a technique in which facial features, i.e., positions of parts of a face, are estimated through statistical data by using two front and side facial shapes and a likeness of persons with its facial expression modified is created based on the estimations. However, this technique has a problem that the facial features of an original image cannot be correctly found since the estimation of the facial features depends on statistical data when the modified likeness of persons is created by using the two front and side facial shapes.
As another three-dimensional caricature creation technique, the Korean Patent Laid-Open Publication No. 2001-69820 (entitled “Method and System for Obtaining a Three-Dimensional Facial Image from a Two-Dimensional Facial Image”) discloses a technique in which contours of an eye, nose, ear, eyebrow and face, a contour of a ridge of a nose, and special features of hair, etc. are extracted from front and side photographs, and then a plurality of three-dimensional facial shapes similar to the extracted facial features are selected from a three-dimensional facial shape database (accumulating a number of faces of actual persons) such that a user can select the most similar three-dimensional facial shape to his own facial photograph. However, since this technique obtains the most similar three-dimensional facial shape through a simple comparison with the pre-constructed facial shape database, it requires additional manual work by a retoucher for the correction of finer details.